Refrigerating apparatus



Sept. 29, 1964 J. H. HEIDORN REFRIGERATINGAPPARATUS Filed Dec. 12, 1963N %R 'Y T0 E MD N I R V5 0 WH 0T H T a A M 1 0 Wm M m United States late'nt O 3,150,503 REFRIGERATING APPARATUS John H. Heidorn, Dayton,Ohio, assignor to General Motors Corporation, Detroit, Mich, acorporation of Delaware Filed Dec. 12, 1963, Ser. No. 330,181 Claims.(Cl. 62-324) This invention pertains to refrigerating apparatus and moreparticularly to means for initiating and accomplishing reverse cycleoperation of a refrigerating system.

Reversed refrigeration cycling can be used for heating a room or meltingfrost from an evaporator. It is especially effective for melting frostfrom an evaporator because it applies the heat internally within thefrost coating. The use of reversed cycling has been retarded by the costof the control system and doubts as to the reliability of the reversingmechanisms.

It is an object of this invention to provide an improved, inexpensiveand simplified control system for reversing a refrigerating system.

'It is another object of this invention to provide a reversing controlwhich can be readily controlled by a fluid motor.

It is another object of this invention to combine a reversing controlfor a refrigerating system with a fluid motor which will also operate aswitch to control the fan or air circulation.

These and other objects are attained in the form shown in the drawingsin which a slide member has a leaking piston at its opposite endsfitting within a cylinder. The slide membercarrie's a spring pressedslide valve member which alternately connects the compressor suctionconnection witheither the condenser or the evaporator. The dischargeconnection of the compressor connects to the interior of the cylinderand the gas flows around either end of the slide valve member, dependingupon its position, to either the evaporator or the condenser. The slidemember is positioned by the differential of pressure on its oppositeends controlled by a double throw valve member providing a connectionalternately between the opposite ends of the cylinder and the suctionconduit. A fluid motor responsive to the temperature adjacent the outletof the evaporator when it reaches a predetermined low temperatureoperates the double throw pilot valve to defrost position to cause thepressure differential on one of the slide member pistons to move theslide valve into position to connect the suction conduit with thecondenser. The compressor discharge is then effectively connected to theevaporator to defrost the evaporator. A plungertype switch is alsocontrolled to de-energize both the condenser and evaporator fans duringthis period. Normal control of the system is by a thermostatic switchresponsive to either compartment or room air or evaporator temperature.When the evaporator reaches a sutficiently high temperature to assuredefrosting, the fluid motor is expanded to move the double throw pilotvalve to the normal position. The differential in pressures on the onepiston of the slide member causes it to move to the normal position atthe opposite end and return the refrigerating system to normalrefrigeration.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

1 FIGURE 1 is a diagrammatic view of a reversed cycle refrigeratingsystem embodying a reversing control illustrating one form of myinvention.

FIGURE 2 is a fragmentary sectional view taken along the line 22 ofFIGURE 3 illustrating the pilot valve.

3,150,503 Patented Sept. 29, 1964 FIGURE 3 is a sectional view takensubstantially along the line 33 in FIGURE 1. 1

FIGURE 4 is a fragmentary transverse sectional view taken along the line4-4 of FIGURE 3 and FIGURE 5 is a sectional view taken along the line5--5 of FIGURES 2 and 3.

Referring now more particularly to FIGURE 1, there is shown a reversingcycle refrigerating system including a sealed motor compressor unit andtwo heat transfer units 22 and 24. Normally the unit 22 will operate asthe condenser, and the unit 24 will operate as the evaporator. Howeverwhen the cycle is reversed, the unit 22 becomes the evaporator and theunit 24 will become the condenser. This system may be used for cooling ahousehold refrigerator or for air conditioning, such as cooling a roomor a house. The unit 22 is shown as being enclosed within an enclosure26 which may be the machinery compartment of a household refrigerator oran air conditioner. A fan 28 driven by an electric motor 30 circulatesair into heat transfer relation with the heat transfer unit 22. If it isused for household refrigerator, the

room air will be circulated in heat transfer with the unit 22 while ifit is used for air conditioning, outside air will be circulated in heattransfer with the unit 22. If desired water may be used as the coolingmedium and the electric motor 30 may be used to operate a water pump tocirculate water in heat transfer with the unit 22.

The unit 24 may be used to cool the air within a household refrigeratoror it may be used to cool the air in a room or a house if used for airconditioning. It is enclosed within an enclosure 32. The air in theenclosure is circulated in heat transfer relation with the heat transferunit 24 by a fan 34 driven by an electric motor 36. The sealed motorcompressor unit 20 is provided with a discharge conduit 38 connectingwith the inlet 40 of a reversing valve 42. The sealed motor compressor20 also has a suction conduit 44 connecting with the outlet 46 of thereversing valve 42. This connection is shown diagrammatically in FIGURE1 by the use of a dot and dash line.

The reversing valve 42 is also provided with a connection 48 connectingthrough the conduit 50 with the one end of the heat transfer unit 22which will be the inlet end when the unit 22 operates as a condenser.The reversing valve 42 is also provided with a connection 52 connectingwith a conduit 54 to the top of the heat transfer unit 24. Thisconnection serves as the outlet of the heat transfer unit 24 when itoperates as an evaporator. The opposite end 56 of the heat transfer unit22 is connected through the flow control valve or restricter 58 and theconduit 60 with the other end of the heat transfer unit 24. When theunit 22 acts as a condenser, the liquefied refrigerant flows through theoutlet 56 and the valve 58 and expands and flows through the conduit 60into the unit 24. When the reversing valve 42 is reversed, therefrigerant flows in the opposite direction to heat the unit 24 and coolthe unit 22.

I According to my invention, the flow of refrigerant within thereversing valve 42 is controlled by a slide valve 62 in the form of aD-type valve which may be made of nylon. This D-type valve has itsperiphery sealed to the Walls of the cylinder 64 and within theperiphery contains the cavity 66 for providing a connection between thesuction connection 46 and either the connections 48 and 52 connectingwith either the heat transfer units 22 or 24. This arrangement alsoprovides a connection between the discharge connection 40 and either ofthe connections 52 or 48 by the flow of refrigerant around the D-typeshaped valve 62.

The D-shaped valve 62 is provided with notches 68 at its opposite endswhich fit slidably on the cages 70 provided at the opposite ends of themetal frame 72. A bowed wire spring '74 fits into a groove extendingaxially in the D-shaped valve member 62 and at its ends extends throughapertures in each of the cages 71 so as to apply a spring force upon theD-shaped valve 62 so as to hold the D-shaped valve member 62 against thewalls of the cylinder 64 to provide a satisfactory seal. The frame 72has connected to it, on the outside of each of the cages 70, a sinterediron piston 76 provided with a bleed hole 78. This connection is made bya spring holding arrangement which includes a conically shaped valveprovided at each end having a valve stem 82 passing through each of thepistons and each of the cages and provided within each of the cages acompression type coil spring 84 which holds the piston resiliently inengagement with the adjacent cage 70. A retainer 86 retains the springof the stem. This arrangement prevents misalignment of the pistons 76,

At the left end of the cylinder 64 there is provided a cylinder head 88provided with a central passage 91 having a valve seat cooperating theconical valve 80. This passage connects with an end chamber 92 providedbetween the head 88 and the threaded cap 94. This end chamber 92 isconnected by a passage 96 extending through the walls of the cylinder 64to a passage 98 in a valve head 121 provided in the head at the oppositeend of the cylinder 64. The passage 98 connectswith a valve chamber 123in the head 121. The head 121 is also provided with a coaxial passageand seat 125 cooperating with the adjacent conical valve 80 on the slideframe 72 and connecting through a passage 127 with a valve chamber 129.The valve chamber 129 contains a valve 131 adapted tocooperate with avalve passage and valve seat 133 connecting with a central passage 135.The valve 131 is connected through an integral connection 137 with anoppositely oriented valve 139 located in the valve chamber 123 andcooperating with the valve seat and valve passage 149 connecting thevalve chamber 123 with the central passage 135. The two valve members131 and 139 are therefore integrally connected by the connection 137 soas to operate as a double throw valve member in which they alternatelymake sealing engagements with their respective valve seats 133 and 149.These valves are also provided with conical closing springs 151 and 153at their opposite ends. The passage connects with an end chamber 155which in turn connects through a passage 157 with the suction conduit46.

The connection 137 is notched at its center point as illustrated inFIGURES 2 and 3 to receive the forked end of a valve operating lever 159pivotally mounted upon and sealed to a diaphragm 161 sealed to the wallsof the cylinder 64 by the cap 163. The diaphragm 161 also forms asealing wall for the chamber 155. The outer end of the lever 159 extendsthrough a central aperture in the cap nut 163 and is pivotally linked tothe lower end of an operating rod 165. This operating rod 165 extendsthrough an aperture in the toggle extension arm 167 and has on oppositesides thereof a set of adjustable contact nuts 169 for operating the rod165. The extension arm 167 is a part of the toggle blade 171 pivoted atone end to the U-spring 173 and pivoted at its other end to the follower175 of the power element diaphragm 177. The cooperating toggle link 179is provided between the follower 175 and the other end 181 of theU-spring 173. The toggle operation is adjusted not only by the nuts 169,but also by the adjusting screw 183 which threads through a bracketfastened to the walls of the cylinder 64 and presses against the end 181of the U-spring 173 to apply a column loading to the toggle links 171and 179 to create a satisfactory toggle snap action mechanism. Thediaphragm 177 is sealed within the cup member 185 to form a fluid motormounted on the walls of the cylinder 64. This cup member has itsinterior connected through a capillary tube 187 with the thermostat bulb189 preferably mounted at the top of the heat transfer unit 24 whichserves as the outlet when this unit operates as an evaporator.

FIGURE 1 shows the system in the condition at the end of the defrostingcycle with the temperature of the heat transfer unit 24 having risensufficiently to cause the diaphragm 177 to be moved upwardly to trip thetoggle blades 171 and 179 to their upper position. The toggle blade 171has a second extension arm 191 which depresses the plunger of the switch193 to close the circuit to the fan motors 3t) and 36 to resumeoperation of the fans 28 and 34. For this purpose the supply conductor195.comnects through the conductor 197 and the switch 193 to theconductor 199 connecting with the branch conductors 226 and 222connecting respectively with the fan motors 36 and 30. These fan motors36 and 30have the second conductors 224 and 226 connecting with theconductor 228 which connects through the thermostatic switch 239 withthe second supply conductor 232. The thermostatic switch 230 is providedwith a fluid operating motor 234. connected by a capillary tube with thethermostat bulb 236 located in the air stream of'the heat transfer unit24. The fluid motor 234 is provided with a snap action mechanism formedof toggle blades similar to the toggle blades 171 and 179 which areassociated with the fluid motor formed by the cup member 185 and thediaphragm 177. The conductors 228 and also connect with the sealed motorcompressor unit 20 so that it will operate whenever the switch 230 isclosed by reason of a high temperature of the bulb 236.

The fluid motor formed by the cup member 185 and the diaphragm 177 hasmoved the rod '165 downwardly to pivot the lever 159 in the clockwisedirection to close the valve 139 upon its seat 137 and to move the valve131 to the open position. This causes suction to be applied from thesuction connection 46 through the passage 157, the chamber 155, thepassage 135, the valve passage 133, past the open valve 131 through thevalve chamber 129, the passage 127 and 125 to the right end of thecylinder 64. This will apply a pressure differential upon the piston 76which will then have discharge pressure applied to its left side fromthe discharge inlet 40 and the suction pressure applied to its rightside so as tocause the frame 72 to be moved to the right carrying theD.-shaped valve 62 with it until the cavity in the valve 62 bridges thesuction inlet 46 with the evaporator connection 52. The bleed orifice 78in the piston 76 at the opposite endprevents the occurrence of a vacuumat the opposite end. The conical valve 80 at the end of this movemententers and closes the passage 125 to stop the flow of gas to the suctionconnection 46 after this movement is accomplished. The dischargeconnection 40 is then effectively connected to the connection 48connecting through the conduit 50 with the inlet of the heat transferunit 22 which then operates as a normal condenser.

The system continues to operate in this condition until the temperatureof the switch 230 is satisfiedto cause the opening of this switch.Should the evaporator 24 at any time become coated with frost to anobjectionable amount, the insulating effect of the frost on theevaporator 24 when the switch 230 is closed will cause the temperatureadjacent the bulb 189 to become abnormally low. This will cause thefluid motor formed by the cup member 185 and the diaphragm 177 to movethe diaphragm 177 downwardly to pull the toggle blades 171 and 179downwardly with a snap action to lift the arms 167 and 191. The liftingof the arm 191 will release the plunger of the switch 193 causing it toopen and deenergize the fan motors 30 and 36. The rod 165 will also belifted to move the lever 159 in the counterclockwise direction to moveboth valves 131 and 139 downwardly thereby moving the valve 131 intoengagement with the seat 133 and to move the valve 139 to open position.This connects the left end of the cylinder 64 through the passage 90,the chamber 92, the passages 96 and 98, the chamber 123, the valvepassage 149, the chambers 135 and 155 with the passage 157 connectingwith the suction connection 46. This will apply a pressure differentialtothe left piston 76 since discharge pressure will be applied on itsright face from the discharge connection 40 and suction pressure will beapplied to its left face through the open valve 139 as previously descried. This pressure diflerential on the left piston 76 will cause theframe 72 and the slide valve 62 to move again to the left to theposition shown in FIGURE 3 to start another defrosting cycle which willcontinue until the bulb 189 reaches a predetermined high temperature andagain moves a fluid motor formed by the diaphragm 185 and 177 back tothe position shown in FIGURE 1. The switch 23th will be closed duringthis operation by reason of the higher temperature prevailing in thevicinity of the bulb 238.

Thus through thi relatively simple arrangement I have provided anautomatic defrosting control for reversing the refrigerations cycle todefrost the evaporator. cycle will be automatically terminated by thesame mechanism used for initiating the defrost cycle. By using a fluidmotor to operate a pilot valve I eliminate the use of magnetic or otherelectrically operated valves which are commonly used to control thereversing valve. This makes the system less expensive and more reliable.The use of the fluid motor to open the switch 193 further simplifies thecontrols.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. Refrigerating apparatus including first and second heat transfermeans each having inlet and outlet connections, one of said inletconnections being connected to one of said outlet connections,circulating means for circulating a heat transfer medium in heattransfer relation with one of said heat transfer means, a compressorhaving inlet and outlet connections, a reversing valve connected to theoutlet and inlet connections of said heat transfer means and saidcompressor operable to reverse the connections between said compressorand said heat transfer means, fluid pressure means for operating saidreversing valve, a pilot valve means for controlling said fluid pressuremeans to operate said reversing valve, and a fluid motor having meansfor operating said pilot valve means and for controlling saidcirculating means.

2. Refrigerating apparatus including first and second heat transfermeans each having inlet and outlet connections, one of said inletconnections being connected to one of said outlet connections,circulating means for circulating a heat transfer medium in heattransfer relation with one of said heat transfer means, a compressorhaving inlet and outlet connections, a reversing valve connected to theoutlet and inlet connections of said heat transfer means and saidcompressor operable to reverse the connections between said compressorand said heat transfer means, fluid pressure means for operating saidreversing valve, a double throw pilot valve means for controlling saidfluid pressure means to operate said reversing valve means to and fromreversing position, electrical operating means for said circulatingmeans, a switch for controlling said electrical operating means, a fluidmotor, and snap acting means operatively connecting said fluid motorwith said pilot valve means and said switch.

3. Refrigerating apparatus including first and second heat transfermeans each having inlet and outlet connections, one of said inletconnections being connected to one of said outlet connections, acompressor having inlet This and outlet connections, means forming acylindrical chamber having its interior connected to said compressorinlet and outlet connec ions andto the remaining inlet and outletconnections of said heat transfer means, a slide means within saidchamber having alternate positions for alternately connecting saidcompressor inlet and outlet connections with said remaining inlet andoutlet connections of said heat transfer means, said means forming acylindrical chamber including a valve means at one end of said chamberhaving fluid connections with one end of said chamber and with saidcompressor inlet connection, a fluid motor, and snap acting meansoperatively connecting said fluid motor and said valve means forcontrolling the positioning of said slide means.

4. Refrigerating apparatus including first and second heat transfermeans each having inlet and outlet connections, one of said inletconnections being connected to one of said outlet connections, acompressor having inlet and outlet connections, means forming acylindrical chamber having its interior connected to said compressorinlet and outlet connections and to the remaining inlet and outletconnections of said heat transfer means, a slide means within saidchamber having alternate positions for alternately connecting saidcompressor inlet and outlet connections with said remaining inlet andoutlet connections of said heat transfer means, said means forming acylindrical chamber including a valve means at one end of said chamberhaving fluid connections with the opposite ends of said chamber and withsaid compressor inlet con nection for alternately connecting either endof said chamber with said compressor inlet connection, a fluid motor,and snap acting means operatively connecting said fluid motor and saidvalve means for controlling the positioning of said slide means.

5. Refrigerating apparatus including first and second heat transfermeans each having inlet and outlet connections, one of said inletconnections being connected to one of said outlet connections, acompressor having inlet and outlet connections, means forming acylindrical chamber having its interior connected to said compressorinlet and outlet connections and to the remaining inlet and outletconnections of said heat transfer means, a slide means within saidchamber having alternate positions for alternately connecting saidcompressor inlet and outlet connections with said remaining inlet andoutlet connections of said heat transfer means, said means forming acylindrical chamber including a valve means at one end of said chamberhaving fluid connections with the opposite ends of said chamber and withsaid compressor inlet connection for alternately connecting either endof said chamber with said compressor inlet connection, electricallyoperated means for circulating a heat transfer medium in heat transferrelation with one of said heat transfer means, a switch for controllingsaid electrically operated means, a fluid motor, and snap acting meansoperatively connecting said fluid motor to said switch and said valvemeans.

References Cited in the file of this patent UNITED STATES PATENTS2,714,394 Moran Aug. 2, 1955 2,765,628 Anthony Oct. 9, 1956 2,875,780Martin Mar. 3, 1959 2,976,701 Greenawalt Mar. 28, 1961 2,991,631 RayJuly 11, 1961

1. REFRIGERATING APPARATUS INCLUDING FIRST AND SECOND HEAT TRANSFERMEANS EACH HAVING INLET AND OUTLET CONNECTIONS, ONE OF SAID INLETCONNECTIONS BEING CONNECTED TO ONE OF SAID OUTLET CONNECTIONS,CIRCULATING MEANS FOR CIRCULATING A HEAT TRANSFER MEDIUM IN HEATTRANSFER RELATION WITH ONE OF SAID HEAT TRANSFER MEANS, A COMPRESSORHAVING INLET AND OUTLET CONNECTIONS, A REVERSING VALVE CONNECTED TO THEOUTLET AND INLET CONNECTIONS OF SAID HEAT TRANSFER MEANS AND SAIDCOMPRESSOR OPERABLE TO REVERSE THE CONNECTIONS BETWEEN SAID COMPRESSORAND SAID HEAT TRANSFER MEANS, FLUID PRESSURE MEANS FOR OPERATING SAIDREVERSING VALVE, A PILOT VALVE MEANS FOR CONTROLLING SAID FLUID PRESSUREMEANS TO OPERATE SAID REVERSING VALVE, AND A FLUID MOTOR HAVING MEANSFOR OPERATING SAID PILOT VALVE MEANS AND FOR CONTROLLING SAIDCIRCULATING MEANS.